Dialysis Filtration Controller Using Substance Distribution Feedback

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Solution Overview

Problem

Current bodily fluid treatment devices, such as dialysis machines, face challenges in effectively controlling filtration rates to prevent hypotension and intradialytic symptoms like nausea and blood pressure drops, as they rely on uncontrolled or random filtration rate adjustments rather than targeted fluid management.

Innovation Solution

A controller that defines a target relation between measured values reflecting tissue substance mass/concentration and distribution space, calculates these values during treatment, and outputs signals to control the filtration rate to achieve a predetermined target relation, using methods like ultrafiltration boluses and steady-state curve approximation to ensure controlled fluid management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If uncontrolled or random filtration rate adjustments are used, then device complexity is reduced, but patient safety and treatment effectiveness deteriorate due to hypotension and intradialytic symptoms

Engineering Contradiction:
Improvepatient safetyVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system continuously monitors the relationship between substance concentration (e.g., hemoglobin) and distribution space (blood volume), comparing actual values against a target relation. Based on this feedback, the filtration rate is dynamically adjusted to maintain the target relationship, preventing hypotension and intradialytic symptoms while ensuring reliable patient safety

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system automatically calculates the target relation between substance concentration and distribution space, determines optimal filtration rates, and executes control actions without requiring manual intervention. The controller self-regulates the filtration process by integrating measurements, performing calculations, and adjusting parameters autonomously

Inventive Principle:
Principle #25Self-service

2Productivity

If filtration rate is increased to shorten treatment duration, then productivity is improved, but patient comfort and safety deteriorate due to hypotension and intradialytic symptoms

Engineering Contradiction:
Improvetreatment efficiencyVSAvoidhypotension and intradialytic symptoms
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The filtration rate is made dynamic rather than static, continuously adapting during the treatment session. The system calculates optimal filtration rates at different time points based on the current relationship between substance concentration and distribution space, allowing aggressive filtration when appropriate and conservative filtration when needed, thus maximizing productivity while preventing harmful effects

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the filtration rate parameter dynamically based on calculated target relations. By adjusting this key parameter in real-time according to measured substance concentration and distribution space values, the system achieves optimal treatment efficiency without causing hypotension or intradialytic symptoms

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If precise control of filtration rate is implemented, then patient safety and treatment effectiveness are improved, but device complexity and measurement requirements increase

Engineering Contradiction:
Improvefiltration rate control precisionVSAvoidmeasurement and control system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control system integrates multiple functions into a single unified controller: it measures substance concentration and distribution space, calculates the target relation between these parameters, determines optimal filtration rates, and executes control actions. This multi-functional integration achieves precise filtration control while managing device complexity through consolidation rather than separate specialized components

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2560700B1Controller for controlling a filtration rate, apparatus, device and digital storage means
Publication Date: 2020.11.18 FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH
  • EP2560700B1 patent drawingFigure 1
  • EP2560700B1 patent drawingFigure 2
  • EP2560700B1 patent drawingFigure 3

AI summary

The present invention relates to a method for controlling of a filtration rate during treatment of a body fluid, particularly during haemofiltration or dialysis of a patient by means of a respective device, comprising the steps of defining a target relation, or a development during dialysis thereof, between one or more calculated or measured value(s) reflecting the mass or the concentration or the volume of a substance comprised by a tissue or a bodily fluid of the patient, and one or more calculated or measured value(s) reflecting a distribution space of the patient or an approximation thereof; during dialysis repeatedly calculating or measuring of value(s) reflecting the mass or the concentration or the volume of the substance and/or reflecting the distribution space or an approximation thereof, and determining the relation there between at least once; and controlling the filtration rate of the body fluid treatment device such that the determined relation is or approaches the target relation or aims to do or be so. It also relates to a controller, an apparatus, a device, a digital storage means, a computer program product, and a computer program.